\ .'i \ M MON1 



: uhorl. UMI:I||\ Mttainiii". i kiiiM li. A pt \ 



elm i il.ir Mm- ii. -I \er\ eMinplicMted, understood in the 



Beiise of a redm-im- ehaiiire. Si j)ln HIM I lulu- l:ir_- rn.-il 



ill- lllllrh developed :ill(| broad. lateral-* i U ie-| ioi lit ei I , Vel\ 

 ill ill (In- ill\ yollll^er form-. 



Tin- -rim be-ins in the upper pMrl of t he middle 



.1 lira ir. \\iili the ^ronp N////. N////V///////. a, ir, />.<, f//v//////. 



which sl:iinl Very cle to typical / 



>7/A//M/< >. diH'ei-inu' from them onlv in ><>ine\vhat more developed 



loli^, the :i|>m'.Mr:inrf ol' tllltel'eles on the ribs :illd t he 



.nee of :in e\!ern:il t'nri'ow. so th:it it is in the hiu;lie>t d< 



|.rol..-i!.le th:it Iiotli P-IUTM spring iVom :i coininon rod . e-|.e.-i;dlv 



U PerisphincteS is inclined in :i lii^'li deii'i'ee lo develop ;in 



'ii:il furrow. r l'lu-s' st.-ind \erv elo>e to forms from the 



h'wer :ind middli' }>:\r\^ of the upper ,TurM>-ie. MS Sim. contorlum, 



il.. Mild A<iri'l<'nl in nil). (Jl'in. (Jl'MdllMlly U ellMllire of Slleh 

 M kind >irp> in. M> lo vephiee the ori^iiiM lly present divided rihs 

 with more and more simple ones until the lir^t Mre entirely rephieed. 

 whilst Mt the sMine time the rilts on the body-chamber sepMi'Mte 

 moi-e :nid more. Mini become stroiiu'lv swollen. Out of these the 

 mely developed. sti'Miij^i.' s|)ec;ies of the Titlion Mre evolvel. 

 f>r which the ^eims WM> ori^iiiMlly established, with in pMrt ver\ 

 prominent, in pMrt rudimentMry sculpture, decidedly re(luc t -d 

 lolmlMi' mMi-kinu's, Mini wit'.i the external lobe of the aperture 



ipwards. 



The highest development is MttMiued by Simoeentx in the 



Titlnm. whei'e M u'reat diversity of forms MI'C developed ; but 



the genus .-ilreMdy begins to lie out in t he upper Tit lion. The 



"-icMlly olde-1 forms are (list ril)iited in the MetliterrMneMii 



'II MS in middle KuropeMii .JurM-sic. more prominently in the 



hitter. The yoimirer ty|)es Mre Mlmoxt entirely eonlined t o the 



.Mediierr:iiie::ii pro\'i lice. ;i lid M | | MM r north WMI'ds in (plite isolated. 



extremely r:i re ^pecies (Sim. Bandenense Mild /hmhlii-ri). 



Bmoi ii. r r. i l-j. ii-s. I;T<>. 1:7 1. 



OIM :: i i. A OF AMMOXFTI>. 



There are ronstantly found .-ss-oc'iMted with. Mini 

 within the aperture of Ammouite->. horny or >helly plate-, which 



